Since desalination projects require enormous amounts of energy, researchers are working on alternative solutions
What if a dome, the Sun and a water supply (either sea or bore water) could provide limitless quantities of drinkable water? A team of researchers at Cranfield University has been evaluating the patented technology of the British firm Waterlâ€™eau by building a working scale model at 1:100 size and looking at expected productivity and costs as well as the most efficient materials for the structure and for heat storage within the dome. The results of the research showed that each Waterlâ€™eau dome could deliver up to 40,000L of clean water every day, enough to meet the needs of 8,000 people, based on World Health Organization figures, including water for agriculture and farm animals.
The current situation in the desalination industry
Î™t is becoming a necessity for the desalination industry to make the shift away from fossil fuels, as desalination projects require enormous amounts of energy. The current output of such plants globally is more than 70 million m3 per day, and growing populations and their demands for higher standards of living mean this figure will need to grow exponentially to meet their needs. Especially in the Middle East and North Africa, the gap between demand for water and its actual supply is said to be around 42 km3 per year, according to the World Bank figures, and is expected to increase by five times that by 2050. There is however ongoing research on various hybrid energy systems for water desalination (1), (2) while solar-powered desalination plants, in theory and in practice, have been under development since the start of the 21st century.
The solar-dome desalination system
Malcolm Aw, founder of Waterlâ€™eau, had the idea of using solar enhanced greenhouses for desalination, as the concentrated solar energy due to the strategically-arranged banks of mirrors would speed up the natural process of evaporation within the domed greenhouse structures. The inflow of seawater, drawn by gravity, travels via enclosed glass aqueducts into the dome (which has a diameter up to 80m), where it is boiled, distilled and then collected in cauldrons. The dense steam produced falls as a tropical rainstorm within the dome as clean and pure water which is then piped to reservoirs in order to serve the local needs in water.
Up to now, the â€˜greenâ€™ desalination technologies have been relatively expensive in comparison to fossil fuel-based approaches and World Bank figures claim that using current technologies, each litre of desalinated water costs around $1 more. The analysis of the researchers from Cranfield University and the simulation of the full scale plant showed that over the 35 year life cycle of a dome, each litre of clean water would cost under 2 US cents a litre to produce! In order to confirm this estimation, a field demonstrator at a scale of 1:20 has been designed and is about to be built in Spain. Cranfield and Waterlâ€™eau are looking for partners to invest in the project, contributing to the Â£350,000 needed for this final demonstration stage before full working plants become commercially available, while governments in Australia and North Africa have already expressed in purchasing one when they do. According to the business plans worked up by Cranfieldâ€™s School of Management, a business value of Â£40 million over five years of operation has been predicted.
Source: Innovators Magazine